code: def test_empty(self, pipeline):
      # make sure that various models handle the degenerate empty case
      pipeline("")
      pipeline("--")
  
imports: import pytest
  import stanza
  from stanza.utils.conll import CoNLL
  from stanza.models.common.doc import Document
  from stanza.tests import *
  from stanza.tests.pipeline.pipeline_device_tests import check_on_gpu, check_on_cpu
label_desc: Use image node_id 8 for calling the TestEnglishPipeline obj's underlying member method code with example usage: obj.test_empty(pipeline) without return types